This is a whole pile of <ahem> flawed logic. First of all, Gene Roddenberry never hinted that Star Trek took place in an "alternate universe". Quite the contrary, in fact.
"The 1960s were one of the most volatile times in American history, and Roddenberry saw it as an opportunity to provide audiences with something uplifting and optimistic about the future. It was his vision of where he hoped humanity would someday evolve, learning from the mistakes of its past. In short, he was hoping to somewhat lead by example: Depict the world operating harmoniously, and perhaps people will believe it is possible."
The future. OUR future, not the future of some "alternate universe".
The "alternate universe" BS crept in only after Roddenberry died, when the current generation of Star Trek writers and producers were too chicken shit or unimaginative to create something new....
Here are two proofs that
Star Trek happens in an alternate universe:
Proof One:
Gene Roddenberry and other
Star trek writers might never have intended to write
Star Trek as happening in a alternate universe from ours, but that they did often write
Star Trek stories that must happen in alternate universes than ours. As a fan of both history and science fiction, I notice a lot of historical references in science fiction stories and programs such as
Star Trek. Many of those historical references are accurate. Many are inaccurate.
Everything that a fictional character says about an exotic setting like the future or another planet must be true. In a story set in the here and now, audience members have many other sources of information about the here and now and don't have to relay on what the fictional characters say for information about the here and now. In a story set in a distant time and/or place, the audience doesn't have those other sources of information, and is forced to rely only on the information in the story. Therefore the writer is obliged to include only accurate information about the setting of his story.
With one exception. A writer can include inaccurate information about his fictional setting in the story if the writer intends for the fact that it is inaccurate to be discovered during the story. If, for example, a character lies or is mistaken, that has to be discovered during the story as part of the planned plot. And in a series of many stories or episodes written by many different writers, every false statement must be planned to be discovered during the plot of the story or episode in which it is made, unless there are plans for it to be discovered later on in a multi episode story arc.
Since the several inaccurate historical references in various
Star Trek episodes, from TOS onward, were not revealed as inaccurate during the episodes in which they were made, or in any planned multi-episode story arc, the writers of those episodes could not, if asked about it, claim that they had the characters make those inaccurate historical references as part of a plot plan. Therefore, those inaccurate historical references in various productions starting with TOS must be accurate in the fictional universe of
Star Trek, since the only loophole for inaccurate references is closed. And that puts the fictional universe of
Star Trek in an alternate universe to our universe. It is impossible for
Star Trek to happen in our future, because the past of
Star Trek must be different from our past.
Proof Two:
There is another big reason why
Star Trek must happen in an alternate universe from ours. If you watch crime dramas about advanced police agencies, you will notice that they have many ways of finding out information about someone from their fingerprints, or DNA, or a security camera image of their face, etc., etc., and most of these methods probably work in real life though probably not as fast or as well.
As an amateur historian and genealogist I know that there is much less information, but still a lot, available about persons living in advanced societies in the last few centuries.
So in, for example, a murder mystery set in an advanced society in the last few hundred years, there would be ways for a reader to find out if people with the names of the victim, the murderer, the detective, and other characters lived in that community at the time of the fictional murder, and to check whether they did so and there were reports of that murder at the time.
It is very easy for people able to do the research to investigate any work of fiction set in advanced societies in the present time, or in the last few hundred years, to find out if the events happened and whether any of the characters ever lived when and where the story is set.
And in most cases those investigations will prove that those stories didn't happen. Works of fiction set in advanced societies in the present or in the last few hundred years are usually falsifiable; they can usually be proved to have never happened.
So if the fictional people places, events, and things in a work of fictional were real in the fictional universe of the story but are not or were not real in our universe, the story must be set in an alternate universe where different people, places, events, and things exist or existed. Thus a very large proportion of all fiction ever written happens in countless alternate universes, though those who claim that all fiction happens in alternate universes may be exaggerating.
A number of different
Star Trek productions have future characters traveling to Earth in their past, which is often also in our past as of the present year 2020.
And when
Star Trek characters travel to our past and meet persons, places, events and things which exist in that past but can be proved to not exist or have existed in our past, that proves that
Star Trek happens to an alternate universe than ours.
But never fear. Fans were not constantly describing
Star Trek as happening in an alternate universe back in the days of TOS or for decades afterwards. The vast majority of fans probably believed that
Star Trek was set in our future during the first few decades of fandom. In fact, for all that I know, the majority of fans and casual viewers might still believe that
Star Trek is set in our future.
So Roddenberry's goal of showing an example of a good future to encourage and give hope to fans and casual viewers was accomplished, even though Roddenberry and other
Star Trek creators failed to actually set
Star Trek in our future. The message of hope for a better future was spread and possibly contributed to making our present better than it would have been otherwise, and might possibly make our future better, and certainly sometimes gives comfort to viewers.